1. Technical Field
The disclosure relates to a cam cap constituting a bearing that supports a camshaft. More specifically, the disclosure relates to a cam cap including an oil supply structure for supplying lubricating oil to a sliding section at which the cam cap and a thrust plate slide with respect to each other.
2. Description of Related Art
There is a known configuration in which a camshaft is provided with a thrust plate that is a disk-shaped protrusion in order to restrict the axial movement of the camshaft. Japanese Patent Application Publication No. 9-242523 (JP 9-242523 A) describes a configuration in which a cam cap includes an oil groove for introducing lubricating oil to a sliding section at which the cam cap and a thrust plate slide with respect to each other. The cam cap constitutes a bearing that supports a camshaft provided with the thrust plate. JP 9-242523A describes a configuration in which the lubricating oil is supplied through the oil groove to the sliding section at which the cam cap and the thrust plate slide with respect to each other.
A bearing that supports a camshaft provided with a thrust plate may adopt a configuration, as illustrated in FIG. 7, where a cam cap 110 includes an accommodating groove 112 in which a thrust plate 133 is accommodated and a journal 135 on which the thrust plate 133 is provided is covered with the cam cap 110.
For example, when such a bearing is employed, lubricating oil is supplied to a gap between the journal 135 and the cam cap 110 through a camshaft oil groove 132 of the journal 135 of a camshaft 130. The lubricating oil supplied to the gap between the journal 135 and the cam cap 110 is supplied into the accommodating groove 112.
As illustrated in FIG. 7, a moment in an R1 direction is generated in the camshaft 130 by tension of a timing chain 121 looped over a sprocket 120 attached to the camshaft 130. Thus, the thrust plate 133 is pressed against a first sidewall 112A positioned on the sprocket 120 side, out of first and second sidewalls 112A, 112B of the accommodating groove 112 in the bearing having the above-described configuration. As a result, a load is applied to the first sidewall 112A. As illustrated in FIG. 7, when an accommodating groove in which the thrust plate 133 is accommodated is not provided in a cam housing 108 that covers the journal 135 from below, the accommodating groove 112 is open at a lower end 110C of the cam cap 110, as illustrated in FIG. 8.